Abstract: In this paper, the influence of init ial imperfection and coupling between bending and extension on vibration, buckling and nonlinear dynamic stability of laminated plates is studied. The governing e quation is derived. It is a nonlinear modified Mathieu Equation. Numerical solut ions of 5 typical composite materials namely, Glass-epoxy Scotch-1002, Aramid-epoxy Kevlar-49, Boron-epoxy B4-5505, Graphite-epoxy T300-5208 and AS-3501 are computed. Results reveal that the existence of initial imperfection, and also coupling effect,make the plates much more sensitive to entering parametric resonance with amplitude greater than that of perfect plates. Coupling effect for different composite laminates, especially, for that with few layers, is different. If coupling effect is neglected, the design of plate structures for buckling and dynamic stability would unconservatively be for more than 10%.